CNS: Antagonism of NMDA receptors in CNS. Weak anesthetic, produce analgesia. Usually combined with other anesthetics. Used alone e.g. dental procedures.
Cardiovascular System: Mild myocardial depressant & a mild sympathetic stimulant. HR and BP are usually unchanged. ↑ pulmonary vascular resistance.
Respiratory System: Little effect on respiration.
Adverse Effects:
Nausea/vomiting.
Risk of bone marrow depression.
Inhibits vitamin B-12 metabolism.
Expansion of closed gas spaces. Nitrous oxide is 35 times more soluble in blood than nitrogen. Contraindicated in (e.g. air embolus, pneumothorax, Middle Ear Surgery etc).
Diffuse into the cuff of ETT.
Diffusion hypoxia. After discontinuation, its rapid elimination from the blood into the lung may lead to a low partial pressure of oxygen in the alveoli.
